CPU: Start op::Reduce implementation and implement no-axes case

src/ngraph/runtime/cpu/emitter.cpp

@@ -26,6 +26,7 @@
 #include "ngraph/ops/constant.hpp"
 #include "ngraph/ops/function_call.hpp"
 #include "ngraph/ops/get_tuple_element.hpp"
+#include "ngraph/ops/reduce.hpp"
 #include "ngraph/ops/reshape.hpp"
 #include "ngraph/runtime/tensor_view_info.hpp"
 #include "ngraph/runtime/cpu/call_frame.hpp"
@@ -1081,3 +1082,60 @@ void Emitter::EMITTER_DECL(EmitFunctionCall)
         "        (*cf)(inputs, outputs);\n"
         "    }\n";
 }
+
+void Emitter::EMITTER_DECL(EmitReduce)
+{
+    auto reduce = static_cast<const op::Reduce*>(n);
+    auto reduction_function = reduce->get_reduction_function();
+
+    std::shared_ptr<ExternalFunction> external;
+
+    try
+    {
+        external = function_map.at(reduction_function);
+    }
+    catch (const std::out_of_range)
+    {
+        external = make_shared<ExternalFunction>(reduction_function);
+        function_map.insert({reduction_function, external});
+    }
+
+    auto reductee_type = reduce->get_arguments().at(0)->get_value_type();
+    auto reductee_tensor_view_type =
+        dynamic_pointer_cast<const TensorViewType>(reductee_type);
+    assert(reductee_tensor_view_type);
+    auto reductee_shape = reductee_tensor_view_type->get_shape();
+
+    auto f_result_type = reduction_function->get_result_type();
+    auto f_result_tensor_view_type =
+        dynamic_pointer_cast<const TensorViewType>(f_result_type);
+    assert(f_result_tensor_view_type);
+    auto& f_result_element_type = f_result_tensor_view_type->get_element_type();
+
+    auto result_type = reduce->get_value_type();
+    auto result_tensor_view_type = dynamic_pointer_cast<const TensorViewType>(result_type);
+    assert(result_tensor_view_type);
+    auto result_shape = result_tensor_view_type->get_shape();
+
+    auto& reduction_axes = reduce->get_reduction_axes();
+
+    // Trivial case: no reduction axes (this includes the scalar-reductee case).
+    if (reduction_axes.empty())
+    {
+        TU +=
+            "    {\n"
+            "        call_frame->get_parameterized_tensor_view<" +
+            element_type_names[TI(f_result_element_type)] + ">(" +
+            to_string(outputs.at(0).get_index()) +
+            ")->get_vector() =\n"
+            "        call_frame->get_parameterized_tensor_view<" +
+            element_type_names[TI(f_result_element_type)] + ">(" +
+            to_string(inputs.at(0).get_index()) +
+            ")->get_vector();\n"
+            "    }\n";
+    }
+    else
+    {
+        throw ngraph_error("Reduce: only vectors and matrices are currently supported");
+    }
+}

src/ngraph/runtime/cpu/emitter.hpp

@@ -79,6 +79,7 @@ namespace ngraph
                 void EMITTER_DECL(EmitConstant);
                 void EMITTER_DECL(EmitReshape);
                 void EMITTER_DECL(EmitFunctionCall);
+                void EMITTER_DECL(EmitReduce);
             };
         }
     }

src/ngraph/runtime/cpu/external_function.cpp

@@ -111,6 +111,7 @@ static const OpMap dispatcher{
     {TI(ngraph::op::Constant), &Emitter::EmitConstant},
     {TI(ngraph::op::Reshape), &Emitter::EmitReshape},
     {TI(ngraph::op::FunctionCall), &Emitter::EmitFunctionCall},
+    {TI(ngraph::op::Reduce), &Emitter::EmitReduce},
 };
 
 #undef TI